Description
Certified under BBA Certificate 14/5142 with full Ceretherm system documentation (DoP 00264), Ceresit CT 74 Silicone Render delivers V1 vapour permeability at Sd ≤ 0.14 m — the highest breathability spec in the Renders World silicone range — and is tinted on a dedicated Ceresit mixing machine at our Southampton warehouse in a 25 kg Eco Bucket containing up to 62% post-consumer recycled polypropylene.
Where CT 74 Silicone Render Performs Best — Self-Cleaning UK Facades
Long-term facade performance starts with the right silicone chemistry — CT 74 delivers V1 vapour permeability at Sd ≤ 0.14 m alongside W3 water resistance, 0.6 MPa substrate adhesion, and fire classification up to A2-s1,d0 on mineral wool systems, all backed by BBA Certificate 14/5142 and certified to EN 15824:2017. Part of the premium silicone render range, this pure-silicone-binder thin-coat finish combines Henkel's Double Dry Technology with the integrated BioProtect formula, covering approximately 10–12 m² per 25 kg tub at the standard 2.1–2.5 kg/m² consumption rate.
The chemistry distinguishes CT 74 from the silicate-silicone hybrids and elastomeric alternatives in the same product family. A pure silicone resin binder delivers maximum hydrophobicity and the highest vapour permeability spec across the range, while the Double Dry surface chemistry means rainfall beads and sheets across the finish rather than soaking in — carrying atmospheric deposits with it on every shower. The integrated BioProtect biocide shield resists algae, mould, and fungal colonisation for the full lifetime of the coat, with measurable benefit on the damp, shaded, and north-facing UK elevations where biological growth typically appears within a few years on unprotected surfaces.
Why Trade Specifiers Choose CT 74 Silicone Render
- BBA-Certified Self-Cleaning Performance: BBA Certificate 14/5142 and DoP 00264 cover the full Ceretherm system, giving specifiers the third-party certification that Building Control, NHBC inspectors, and warranty providers typically request — a meaningful documentation advantage over renders certified only at ETA level.
- Highest Breathability Spec in the Range: V1 vapour permeability with Sd ≤ 0.14 m lets moisture vapour pass through the render at the highest rate of any silicone finish in the Renders World portfolio, so damp walls dry outward rather than trapping moisture behind the finish — particularly valuable on solid-wall retrofits and traditional construction.
- Double Dry Self-Cleaning Surface: Henkel's Double Dry Technology creates a hydrophobic surface that sheds dirt with natural rainfall, keeping the elevation visibly clean year after year with virtually no manual washing required — a real advantage on coastal, urban, and high-pollution facades.
- Rainwater Runs Off, Not In: W3 water absorption rating (w ≤ 0.1 kg/m²h⁰·⁵) means wind-driven UK rain sheets off the surface, with a 24-hour absorption value below 0.5 kg/m² — so exposed elevations stay dry and protected through prolonged wet weather.
- Built-In Biological Defence: The BioProtect formula embeds active biocidal agents in the render mass, inhibiting algae, mould, and fungi for the lifetime of the coat without separate biocide treatments — keeping shaded north-elevation facades visually clean where unprotected surfaces typically show green algae within three to four UK winters.
- Over 1,000 Colours Mixed On Site: The full Ceresit Colours of Nature palette is tinted on a dedicated Ceresit machine at our Southampton warehouse, with bespoke RAL, NCS, and competitor-shade matching mixed to order on the same equipment — every tub arrives ready to apply with next-day UK dispatch.
- Eco Bucket Packaging With 62% Recycled Plastic: The 25 kg container is made from up to 62% post-consumer recycled polypropylene and remains fully recyclable at end of life — an industry-leading sustainability spec on commercial projects pursuing BREEAM or LEED credits.
Technical Specifications — CT 74 Data Sheet Highlights
| Property | Value |
|---|---|
| Pack Size | 25 kg Eco Bucket — up to 62% post-consumer recycled polypropylene |
| Binder Type | Pure silicone — water dispersion of silicone and acrylic resins with mineral fillers |
| Grain Size | 1.5 mm — stone texture |
| Density | 1.7 kg/dm³ |
| Coverage Rate | 2.1–2.5 kg/m² — approx. 10–12 m² per 25 kg tub |
| Vapour Permeability | V1 (high) — Sd ≤ 0.14 m to EN 15824 |
| Water Absorption | W3 (low) — w ≤ 0.1 kg/m²h⁰·⁵ to EN 15824 |
| Adhesion to Substrate | 0.6 MPa (≥ 0.08 MPa after ageing) |
| Thermal Conductivity | λ ≤ 0.61 W/(m·K) |
| Impact Resistance | Category I–II (system-dependent) per ETAG 004 |
| Fire Classification (EN 13501-1:2018) | A2-s1,d0 on mineral wool systems · B-s1,d0 on EPS systems |
| Application Temperature | +5 °C to +25 °C (air and substrate); humidity below 80% RH |
| Open Time | Approx. 15 minutes |
| Rain Resistance | 24–48 hours (temperature-dependent) |
| Bio-Protection | BioProtect — algae, mould, fungi (lifetime of coat) |
| Colour Range | Full Ceresit Colours of Nature palette plus bespoke RAL/NCS matching |
| Machine Compatibility | Wagner PC 15, PC 830, SPG PG 20 · 6–10 mm nozzle at up to 40 bar · 8–10 l/min |
| Mandatory Primer | Ceresit CT 16 quartz primer (tinted close to topcoat colour) |
| Shelf Life | 12 months in original sealed packaging, stored dry, cool, frost-free |
| Standard Compliance | EN 15824:2017 · DoP 00264 · BBA Certificate 14/5142 |
How to Apply CT 74 — Substrates, Priming, ETICS Build-Up
CT 74 bonds reliably to a wide range of substrates when paired with the right primer system. For walls with cured cement or lime-cement render (at least 28 days old) and for concrete substrates (at least 3 months old), apply Ceresit CT 16 quartz primer from the exterior render primers range and allow it to dry fully before rendering. On absorbent substrates, a preliminary coat of Ceresit CT 17 deep-penetration primer followed by CT 16 after a minimum 2-hour interval ensures even suction and a uniform finish — the primer selection guide for silicone renders covers substrate-by-substrate priming decisions in detail.
- ETICS Integration: Designed as the decorative finish layer within Ceresit Ceretherm systems — apply over a reinforced basecoat primed with CT 16 after a minimum 3-day cure. Pair with 150 g/m² fibreglass mesh in the reinforcement layer to create a continuous, crack-resistant base for the topcoat.
- Traditional Masonry: Works on properly prepared concrete, brick, and blockwork substrates where CT 16 quartz primer has been applied — matching the primer tint to the render shade gives a consistent tonal base, especially important on white finishes where substrate variation shows through.
- Machine Application: Compatible with Wagner PC 15, PC 830, and SPG PG 20 rendering units running a 6–10 mm nozzle at up to 40 bar, delivering approximately 8–10 l/min — ideal for large commercial elevations where speed and consistency matter most.
- Dark-Colour Guidance: For intense dark colours below HBW 25 on large south-facing facades, CT 76 Solar Protect is specifically formulated with heat-reflective pigments to manage the additional thermal load — CT 74 performs confidently in mid-range and lighter shades on any orientation.
For the full step-by-step application method covering tools, floating technique, and finishing sequence, the thin-coat render application step-by-step guide covers the complete process for UK walls.
Installation Notes — Mixing, Floating, Drying
Stir the entire tub contents thoroughly with a low-speed drill mixer before application — add no more than 1% clean water if the consistency needs slight adjustment. Apply CT 74 at the thickness of the 1.5 mm grain using a stainless-steel float held at an angle, then form the stone-like texture with circular movements using a plastic float held flat against the surface. For the cleanest result, work each elevation in a single wet-on-wet pass rather than breaking the surface into separate sessions.
- Managing Breaks: If a break is unavoidable, press self-adhesive tape along the joint line before pausing and restart from the taped edge — this keeps the join invisible on the finished facade.
- Weather Window: Apply above +5 °C and below 80% humidity, and check a 48-hour weather forecast before starting to ensure rain stays clear during the critical first 24–48 hours of cure — the seasonal application timing guide covers UK weather scheduling throughout the calendar year.
- Drying Schedule: Surface reaches rain resistance approximately 24 hours after application under standard conditions (+20 °C, 50% RH); protect from rain, frost, and direct strong sun during this initial cure window.
- Crew Coordination: The 15-minute open time means one applicator and one float operative working in tandem keeps the wet edge alive across the elevation — the most reliable way to produce a uniform stone finish without lap marks.
Pro Tips From UK Installers Using CT 74
Self-cleaning silicone rewards the small calibrations that determine how a finish ages — particularly tone consistency across primer and topcoat. These site-tested habits keep CT 74 elevations uniform, deep-coloured, and visibly clean for the long term:
- Match CT 16 Primer Tint to the Final Render Colour: Five minutes of planning saves callbacks on shading inconsistencies, especially on white and pastel finishes where even slight substrate variation shows through the topcoat.
- Run Two Operatives Through the 15-Minute Window: One applying, one texturing — keeping the wet edge alive across the elevation is the most reliable predictor of a uniform stone finish without lap marks on facades wider than 4 metres.
- Budget at 2.3 kg/m² Plus 5% Detailing Waste: Use the render coverage calculator to build the full materials list before ordering — the single step that protects an entire materials budget from a mid-project shortfall, and helps avoid batch-mismatch risk when topping up.
- Pair With Atlas Eskimo for Cold-Season Rendering: For winter work between 0 °C and +5 °C, the Atlas Eskimo setting accelerator shortens the curing window and keeps the site schedule manageable through the colder months without compromising film formation.
- Plan a 15+ Year Renovation Pathway Into the Spec: If a client needs a facade refresh further down the line, Ceresit CT 48 or CT 49 silicone paint applied directly over the cured render restores the original tone without stripping back — a straightforward renovation route that extends the system's service life further.
Is CT 74 Silicone Render Right for Your Project?
- Yes — for premium, low-maintenance, BBA-certified facades: CT 74 is the right choice when your project needs a self-cleaning finish with the highest breathability spec in the silicone range (V1 with Sd ≤ 0.14 m), W3 water resistance, and BBA-certified system documentation — ideal for coastal properties, urban facades exposed to pollution, north-facing elevations prone to biological growth, and any project where long-term colour stability and minimal maintenance are the priorities.
- Need a silicate-silicone hybrid for machine-only large-scale work? The CT174 Machine 1.0 mm render offers pump-optimised rheology with a finer stone texture, silicate-silicone double-binder performance, and lower coverage of 1.5 kg/m² — a better fit for commercial elevations above 100 m² where spray productivity and material economy matter most.
- Looking for a premium alternative with extended open time? The broader premium silicone render collection includes premium Atlas silicone systems with 4K aggregate technology and working windows of 30+ minutes — a strong option when the project benefits from a more forgiving application pace or specifier requires Atlas system documentation.
FAQ — CT 74 Coverage, Compatibility, Maintenance
How many tubs of Ceresit CT 74 do I need for my project?
Each 25 kg tub covers approximately 10–12 m² at the 1.5 mm grain size, based on a consumption rate of 2.1–2.5 kg/m². For a typical 60 m² front elevation, budget 5–6 tubs. Adding 5% for site waste and detailing around windows, doors, and reveals ensures enough material to complete the job without interruption, and ordering from the same production batch keeps the colour perfectly consistent across the entire facade.
Can I use CT 74 on older solid-wall properties?
CT 74 achieves V1 vapour permeability with an Sd value of just 0.14 m, meaning moisture vapour passes through the render layer at a very high rate — so older solid-wall properties benefit from effective outward drying rather than moisture building up behind the finish. Pairing CT 74 with CT 16 quartz primer and, on absorbent historic substrates, a preliminary coat of CT 17 deep-penetration primer creates the ideal foundation for long-term performance on traditional construction.
What does the BBA certification actually cover, and why does it matter?
BBA Certificate 14/5142 documents the performance of CT 74 within the full Ceresit Ceretherm system — independent third-party verification of vapour permeability, water resistance, adhesion, durability, and fire performance across the complete build-up. The certification is typically requested by Building Control, NHBC inspectors, mortgage lenders, and insurance-backed warranty providers, particularly on new-build and retrofit projects where third-party performance evidence is required to release funds or sign off completion. BBA-level certification carries more weight in UK regulatory practice than ETA-only certification, which is one reason CT 74 is often specified on developer-led schemes.
Does CT 74 meet fire safety requirements for taller buildings?
CT 74 achieves A2-s1,d0 fire classification per EN 13501-1:2018 when applied over mineral wool insulation within a Ceretherm system, which typically satisfies the requirements for high-rise residential and commercial facades subject to each project's specific fire strategy assessment. On EPS insulation the classification is B-s1,d0. Pairing CT 74 with A1-rated mineral wool delivers the highest-rated compliant specification while preserving the full self-cleaning and breathability benefits of the silicone finish.
What colours are available and can you match a shade from another manufacturer?
CT 74 is supplied across the full Ceresit Colours of Nature palette, tinted on a dedicated Ceresit mixing machine at our Southampton warehouse and ready for next-day dispatch. For projects requiring a shade outside the standard Ceresit range — a specific RAL code, an NCS reference, or a colour matched from another manufacturer's swatch — our team mixes bespoke colours to order on the same equipment. Our warehouse also mixes the Atlas 480-shade SAH palette on a separate dedicated machine, bringing the combined colour choice across both systems to over 1,000 standard shades plus bespoke matching. Browse the colour sample catalogues to view both palettes on physical rendered swatches.
Is Ceresit CT 74 an environmentally responsible choice?
The 25 kg tub is made from 100% recyclable polypropylene containing up to 62% post-consumer recycled plastic, actively reducing virgin plastic demand with every order. The render itself is a water-based formulation with low VOC content, producing minimal emissions during application and curing. The thin application rate of 2.1–2.5 kg/m² generates substantially less material waste per square metre than traditional sand-and-cement renders at 15–20 mm thickness, and the through-coloured, self-cleaning finish eliminates the recurring resource consumption of periodic repainting cycles across the building's service life.
Technical Documentation — CT 74 TDS and BBA